Optical scanners are conventionally used for the measurement of surfaces. However, these are extremely effort-intensive and therefore cost-intensive. They can also detect only the outermost surface of an object. Furthermore, microwave-based methods are known, which, however, demand very effort-intensive optimization processes in order to achieve reliable information.
For example, European Patent EP 1 247 070 B1 discloses a method for surface measurement by means of microwaves which employs the effort-intensive Phase Unwrapping.